An agitator, which is a device for mixing more than two fluid materials, has been widely used over various industrial fields such as chemical engineering, paper making, petroleum industry, heavy industry, or the like.
An example of the agitator according to the related art is shown in FIG. 1. The agitator 10 according to the related art is configured to include a body 1 having a space 2 formed in a hollow inner portion thereof so that fluid may be stored therein; a shaft 3 formed in a central portion of the inner portion of the body 1; a plurality of wings 4 radially formed from the shaft 3, and an impeller 5 rotated by a driving unit (not shown).
The impeller rotates by the shaft formed in the central portion of the body, such that the agitator mixes fluid.
Here, the size, the forming angle, the shape and/or the like of the impeller or the wings are controlled to thereby improve the mixing performance of the agitator. Regardless of the size, forming angle and/or the like of the impeller or the wings, a key dynamical systems structure consisting of two rotational flows remains unchanged. That is, a direct circumferential rotation of fluid materials generated by the shaft by rotation of the impeller and a secondary cross-sectional rotation of fluid materials generated by inertia or a cross-sectional rotational flow generated by an axial flow formed by the impeller. As a result, the dynamical systems structure forms a donut-like streamed surface structure (the toroidal dynamical systems), as shown in FIG. 2. In the case of highly viscous materials (polymeric fluids, emulsions, suspensions, paints, food materials, or the like), the streamed surface stays unchanged forming an invariant surface, due to the absence of turbulent mixing mechanisms (See FIG. 2). In this case, the motion of fluid material is limited such that it moves only along the initially determined streamlined surface during the mixing process, and thereby significantly deteriorated the mixing performance is expected.